Here it is some points to consider:
1°) You don't need any PTF on top of your TSS r16.0 to support MAXACIDSIZE 1024.
2°) Depending on how your owner acids are filled up, you may or you may not decrease his size using the ADD UNDERCUT feature or you have enlarge your acids size.
There are two main cases:
2.1°) Your owner acid is filled up because there are a huge amount of permits done. i.e. your owner acid only owns one resource and it is permitted to tons of acids what makes it to hit the 512k bar.
In that case, your only available choice is either to use MAXACIDSIZE=1024 or MAXAXIDSIZE=512, ORGACIDSIZE=1024.
These options are in the CAKOJCL0(SECPARMS) member, used when you allocate a new secfile.
2.2°) Your owner acid is filled up because he owns several resources and there are a certain amount of permits for each owned resource.
In that case, you can use the ADD UNDERCUT to give ownership of some owned resources to other owner acids.
TSS ADD(new_owner) DSN(XYZ.) UNDERCUT
3°) You can run a TSSFAR with HEADER and SFSTATS option to see what your secfile looks like.
4°) There is no other way to increase either the MAXACIDSIZE or ORGACIDSIZE that to use the TSSMAINS job and then run a TSSXTEND.
You have to allocate new VSAM files accordingly.