I have 500 150 gr flat nose plated bullets and a pound of red dot to use up.
These shot amazing groups in my .308 with 13 gr or red dot but had crazy flyers that would be 8" off from the sub moa group at 100 yards.

I'd like to try the same thing in 30-30, but have no idea what to use for a charge since everything I see indicates 13gr is too much for a 30-30.

I have no other use for the bullets or the powder and would really like some cheap  30-30 plinking

I have seen them posted here but over in Lever section of Armory forum.  Maybe mods can move this post to there.  I want a Marlin 336 to convert to a scout with red dot.  Here is one post I found in archives Show me your scout lever guns

I think he is talking about the powder not the sight.
Sorry, I can't help you, never used red dot for .30/30.

Red dot is a very fast pistol/shotgun powder and is no way meant for use in a .30-.30 rifle. This is how people blow their guns up. Buy some WW-748 or IMR-3031, those are two of the best powders available for .30-.30 lever action rifles.

Get a manual and follow their load advice!

FALSE!

pistol powders are often used for reduced rifle loads
red dot stands out because it is a bulkier powder and tends not to leave as much dead space in the case.

.303 British is the smallest capacity cartridge recommended by Harris for "The Load".

How much smaller is .30-30?

I'd do this: ([.30-30] / [.303]) x 13 = "The Load" for .30-30. Start low, work up to that number.

Visually inspect each charge.

Reference one manual with red dot in .30-30, my Hornady, Nosler, Sierra, Speer, Berger and VihtaVuori manuals seem to have passed it by. What people do and what should be done are necessarily the same thing.

how many manuals go in depth on off the wall stuff like reduced and low recoil loads?

IIRC Lyman does.

I have an older Hornady manual that does.

Full disclosure:  This is just an opinion not based on any technical data.

Look up .357 magnum loads using Red Dot and plated bullets.  Use that as a starting load.  The larger case capacity of the 30/30 SHOULD yield lower pressures and be safe.

I don't see any Red Dot loads for the 30-30 in my 1st, 2nd, 3rd, 6th and 9th editions of Hornady loading manual.

However, RCBS shows Red Dot loads for the .30-30 for their 175 gr bullet (8.0 gr to 8.5 gr) and 187 gr bullet (8.0 to 9.0 gr).

Lyman also shows Red Dot data for their 115 gr bullet (7.0 to 10.0 grains), their 151 gr bullet (6.8 gr to 9.0 gr), their 169 gr bullet (6.5. gr to 8.5 gr) and their 170 gr bullet (6.5. gr to 8.5 gr).

It's important to note however that these are all cast bullet loads and are not designed for jacketed bullets which create more pressure engraving into the rifling.

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I've tried Red Dot with plated 150 grain bullets in my Browning 1885 in .30-30, but accuracy was poor compared to a more normal .30-30 powder like RL-7.

If you try it bear in mind that these plated bullets, while still having a soft lead core and a thin jacket, have more bearing surface than a cast bullet, so be conservative when adapting the load data for them.  As I recall, velocities were limited to around 1400 fps before I started seeing pressure issues, and accuracy was never all that good.

RL 7 let me push the velocity up to 1,875 fps with 1 MOA accuracy.  Any faster than that and I started getting fliers, due to jacket damage in the bore.