I completely disagree about plugging any holes. The oil "particles" are not any bigger only they have more affinity for each other. (totally wrong in detail but accurate in concept).

If your consumption is aggravated by low oil pressure when hot (symptom of excessive bearing clearances) then 40 wt would help and increase the life of the engine... Except upon start-up you will have a major pressure spike and a slight loss of volume to the whole system.

I suggest 20W50 and close watching of the level and oil pressure.

Save pennies for new top-end gasket set and/or head rebuild (assuming all is well with oil pressure, etc. as discussed above). You can easily replace the valve seals and that will help a little too until you can get a proper rebuild (new guides).

Again, check all those other parameters too to see if you need to be saving for a different problem entirely.

Mike!