Hi Calamity,
Many thanks for this greatful help ! VMmaker 2 is really strong tools

At the end, I finish to load this list of modeline :
"496x384_60 24.96KHz 60.00Hz" 15.58 496 512 576 624 384 386 391 416 -hsync -vsync
"640x480_60 31.50KHz 60.00Hz" 25.45 640 664 760 808 480 491 493 525 -hsync -vsync
"2560x240_60 15.66KHz 60.00Hz" 52.12 2560 2664 2912 3328 240 242 245 261 -hsync -vsync
"2560x248_60 16.14KHz 60.00Hz" 54.23 2560 2672 2928 3360 248 250 253 269 -hsync -vsync
"2560x256_58 16.20KHz 58.48Hz" 54.43 2560 2672 2928 3360 256 258 261 277 -hsync -vsync
"2560x264_57 16.20KHz 56.84Hz" 54.43 2560 2672 2928 3360 264 266 269 285 -hsync -vsync
"2560x272_55 16.20KHz 55.29Hz" 54.43 2560 2672 2928 3360 272 274 277 293 -hsync -vsync
"2560x280_54 16.20KHz 53.82Hz" 54.43 2560 2672 2928 3360 280 282 285 301 -hsync -vsync
"2560x288_52 16.20KHz 52.43Hz" 54.43 2560 2672 2928 3360 288 290 293 309 -hsync -vsync
"2560x448_60 15.69KHz 60.00Hz" 52.22 2560 2664 2912 3328 448 467 473 523 interlace -hsync -vsync
"2560x464_60 15.69KHz 60.00Hz" 52.22 2560 2664 2912 3328 464 475 481 523 interlace -hsync -vsync
"2560x480_60 15.69KHz 60.00Hz" 52.22 2560 2664 2912 3328 480 483 489 523 interlace -hsync -vsync
"2560x496_60 16.17KHz 60.00Hz" 54.33 2560 2672 2928 3360 496 499 505 539 interlace -hsync -vsync
"2560x512_58 16.23KHz 58.48Hz" 54.66 2560 2672 2928 3368 512 515 521 555 interlace -hsync -vsync
"2560x544_55 16.23KHz 55.29Hz" 54.65 2560 2672 2928 3368 544 547 553 587 interlace -hsync -vsync
"2560x560_54 16.23KHz 53.82Hz" 54.65 2560 2672 2928 3368 560 563 569 603 interlace -hsync -vsync
In facts, it works fine on my Astro, and I will test soon on my Blast.
Thanks again for your amazing job !!!