year end strategy for MTM

I elected MTM for this year for the first time. I have been treating my investment account (that includes several investments and about 80 day/swing trades per year) as non MTM and plan on using MTM for my prop. trading activities only. Right now I have gains in the long term investments, personal day trades, and prop. trading...all of which greatly exceed carry forward losses. I understand that on MTM tax loss selling is not necessary. I am confused about whether to tax loss sell a few positions in my personal account to offset long term gains that will not be treated as MTM. I have about 20K in losses (on stocks held less than 1 year in my personal account) I could take and don't know whether to do it or not. Please advise. Thanks.